From: Christoph Hellwig <hch@lst.de>
To: Masami Hiramatsu <mhiramat@kernel.org>
Cc: "Elly I. Esparza" <ellyesparza8@gmail.com>,
linux-kernel@vger.kernel.org, will@kernel.org,
akpm@linux-foundation.org, ast@kernel.org, yangfeng@kylinos.cn,
gregkh@linuxfoundation.org, hch@lst.de, qperret@google.com
Subject: Re: [PATCH 2/2] kernel/kallsyms: Prevent bypassing of kprobes blacklist
Date: Thu, 19 Feb 2026 08:20:09 +0100 [thread overview]
Message-ID: <20260219072009.GA5597@lst.de> (raw)
In-Reply-To: <20260219102915.2a79f0713032d95814eee79f@kernel.org>
On Thu, Feb 19, 2026 at 10:29:15AM +0900, Masami Hiramatsu wrote:
> On Wed, 18 Feb 2026 11:48:19 -0300
> "Elly I. Esparza" <ellyesparza8@gmail.com> wrote:
>
> > Kprobes can be used to get the adress of kallsyms_lookup_name() providing
> > access to blacklisted symbols.
> >
> > Add kallsyms_lookup_name() to kprobes blacklist.
>
> NACK, this NOKPROBE_SYMBOL() should be used for the functions which
> is called inside the kprobe callback handler. kallsyms_lookup_name()
> is used when setting up the kprobe, not from the callbacks.
I don't think that's the point Elly made. The point is that
kallsyms_lookup_name + kprobes is used to bypass lacking symbol exports.
So preventing it is a good idea, and this seems like a cute hack for
that. But it really needs a better commit log, and a big fat comment
explaining the slight abuse of NOKPROBE_SYMBOL in the code.
prev parent reply other threads:[~2026-02-19 7:20 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-18 14:48 [PATCH 2/2] kernel/kallsyms: Prevent bypassing of kprobes blacklist Elly I. Esparza
2026-02-19 1:29 ` Masami Hiramatsu
2026-02-19 7:20 ` Christoph Hellwig [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20260219072009.GA5597@lst.de \
--to=hch@lst.de \
--cc=akpm@linux-foundation.org \
--cc=ast@kernel.org \
--cc=ellyesparza8@gmail.com \
--cc=gregkh@linuxfoundation.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mhiramat@kernel.org \
--cc=qperret@google.com \
--cc=will@kernel.org \
--cc=yangfeng@kylinos.cn \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.